U. S. Pat. No. 4,179,580 (Cobb), European Patent 128001 (Kudoh, et al.), and Eberhardt, et al., Journal of Organic Chemistry. Vol. 30, pp. 82-84 (1965) show that it is known that supported alkali metals are useful as catalysts in the coupling of ethylenically-unsaturated hydrocarbons with aromatic hydrocarbons having an active hydrogen on a saturated .alpha.-carbon. The supported alkali metals are more effective than the corresponding unsupported alkali metals in such reactions but are still not as effective as might be desired.
As disclosed in co-pending applications Ser. No. 135,318 (Smith, filed Dec. 21, 1987, and Ser. No. 276,531 (Smith), Ser. No. 276,532 (Smith), and Ser. No. 276,533 (Smith), filed Nov. 28, 1988, it has been found that alkenes can advantageously be coupled with .alpha.-carbon in the presence of a supported alkali metal as a catalyst and about 10-100 mole %, based on the amount of the alkali metal catalyst, of an oxide of sodium, potassium, rubidium, cesium, barium, strontium, calcium, or magnesium as a co-catalyst.
U. K. Patent 1,269,280 discloses a process for the manufacture of alkyl aromatic hydrocarbons using a catalyst prepared by dispersing sodium and/or lithium or an anhydrous potassium compound. The dispersing is carried out by stirring or tumbling the molten metal with the potassium compound, the potassium compound being selected so that it does not melt, sinter or decompose at the deposition temperature.